The present invention relates to an electrophotographic printer, such as a laser beam printer, or an electrophotography apparatus such as an electrophotographic copier. More particularly, the invention relates to an electrophotography apparatus having an intermediate transfer body, and which is suitable for use with an optional unit.
Generally, in a method of producing a color image in an electrophotography apparatus having an intermediate transfer body, an electrostatic latent image on a photoconductive body is developed by a development providing toner apparatus of different colors, a developed toner image of a first color is transferred to the surface of the intermediate transfer body, and further color toner images are superimposed thereon. Then, the composite color toner image on the intermediate transfer body is transferred to a sheet of paper conveyed by a transportation mechanism.
In a color electrophotography apparatus having an intermediate transfer body of this type, the toner images on the photoconductive body are transferred first to the intermediate transfer body from a photoconductive body, and then they are again transferred as a composite image, from the intermediate transfer body to a sheet of paper so as to form a pictorial image thereon, and the color toner image on the paper is heated and fixed by a fixing apparatus after that, so that is can be transported to the outside of the apparatus.
Furthermore, in a color electrophotography apparatus having a duplexer, after the first color toner image on the paper (A side) is heated and is fixed by the fixing apparatus, this paper is turned over in the duplexer, and the paper is conveyed by the transportation mechanism of the color electrophotography apparatus so that a second color toner image can be printed on the back side (B side) in the same way as on the A side.
Furthermore, in recent years, in consideration for the environment, a trend toward energy saving has become conspicuous, and so specifications which emphasize power-saving has become important. For example, in accordance with Energy Star, a power consumption of less than 45 W, for example, is required in a state where an apparatus is in a standby or power-saving mode.
In a conventional color electrophotography apparatus, a voltage power supply of 5V is used in order to drive a control device (a control circuit board), an optical sensor, a display device etc., while a high voltage power supply of 24V, which is higher than the 5V with relationship of efficiency, is used to drive an actuator, such as a motor, a fan, a clutch, a solenoid etc., and there are many cases involving various power supplies.
In the power-saving mode, because it is not necessary for the apparatus to operate, all actuators and the heater in the fixing unit are turned off, so that the power consumption is reduced. In addition, the 24V power supply may be turned off. However, the 5V power supply for driving the control device (including the CPU) cannot be turned off, and other parts, such as the sensors using the 5V power supply, in many cases cannot be turned off. During all of the power-saving mode time, a display unit to display the state of the instruments to an operator can not be turned off for security or operational reasons. In a case where an optional apparatus, such as a duplexer or a sorter, is employed in the color electrophotography apparatus as part of the main body, the energy consumption for each optional apparatus can not be increased in most cases.
In a system including an optional apparatus, it is necessary to maintain a predetermined power-saving specification. On the other hand, where the main body of the color electrophotography apparatus already has a very small margin for the power-saving specification value, a reduction of the power consumption of the main body should be improved. In a case of plural optional apparatuses, or when much energy is used for the optional apparatus itself, there is a limit to use of all of the optional apparatuses and still meet the power-saving specification value. As a means to solve such a problem, Japanese Patent Laid-open No. 9-188037 discloses a method in which a power supply provided in an optional apparatus is cut off when use of the operational apparatus is unnecessary. However, in cases of the control device, which includes a CPU, in the optional apparatus, a problem, such as a malfunction may occur, when the power supply of the optional apparatus is cut off.
Therefore, in the conventional color electrophotography apparatus, there is a problem in that there is a condition in which the apparatus cannot satisfy the power-saving specification fully.
The object of the present invention is to provide an electrophotography apparatus in which the above stated problems are eliminated.
In order to achieve the above object, the present invention provides an electrophotography apparatus comprising a main body having an exposure means to generate a light flux, a photoconductive body for forming a latent image using said light flux, a development device for developing said latent image on said photoconductive body, a transfer device for transferring an image developed by said development device onto a recording medium, and a fixing device for fixing said image on said recording medium, wherein said electrophotography apparatus further includes an optional apparatus which is capable of being mounted on said main body, wherein said main body transmits a switching over instruction to said optional apparatus according to the kind of said optional apparatus when said optional apparatus is mounted on said main body, and a power source system of said optional apparatus is switched over by said switching over instruction.
Furthermore, the present invention provides a color electrophotography apparatus comprising a photoconductive body for forming an electrostatic latent image according to print data classified according to color; plural development units for performing a toner development with said electrostatic latent image; an intermediate transfer body receiving said toner images developed by said development units so as to maintain each image and stack color images; a transportation means to convey paper on which said color toner image on said intermediate transfer body is to be transferred; a transferring apparatus for transferring said color toner image on said intermediate transfer body onto said paper conveyed by transportation means; a discharging apparatus to separate the paper from said intermediate transfer body after said toner image is transferred to said paper by said transferring apparatus; a fixing means to heat and fix said toner image on said paper firmly; and a control device to control each component of the printer; said color electrophotography apparatus further having a duplexer constituted as an optional device to this color electrophotography apparatus for turning over said paper on which said first toner image has been printed and for conveying said paper to said transportation means of said color electrophotography apparatus again, wherein said duplexer has a control device for its exclusive use and an electric power supply for its exclusive use inside of said duplexer. Furthermore, the electric power supply in accordance with the present invention has a circuit structure to selectively feed or cut off the electric power to each component in the duplexer based on control by the control device in said color electrophotography apparatus.
The circuit structure operates to selectively feed said electric power for each component of said duplexer from the electric power supply provided in said color electrophotography apparatus, and said color electrophotography apparatus has a structure to select whether said electric power is fed from the electric power supply provided in said duplexer or from the electric power supply provided in said color electrophotography apparatus. Furthermore, said duplexer indicates to said control device of said color electrophotography apparatus whether said electric power is to be fed or not from said electric power supply of said color electrophotography apparatus according to the constitution of said duplexer.
The control device of said color electrophotography apparatus has a detection means to detect whether said duplexer is to be connected or not connected to said color electrophotography apparatus, and to detect whether said power is to be fed or not fed from said color electrophotography apparatus to each component, whereby said color electrophotography apparatus detects a condition of said duplexer, and in response to the detected condition, said power supply is selected.
The control device of said color electrophotography apparatus has a detection means to detect whether said duplexer is to be connected or not connected to said color electrophotography apparatus, wherein, when said color electrophotography apparatus is in a power-saving mode so that said duplexer is not being operated, said power supply in said duplexer is switched off according to said control signal.
Furthermore, information is transferred from said control device in said color electrophotography apparatus to said control device in said duplexer beforehand, before said circuit structure selects feed/cut of said electric power.
In addition, said electric power supply inside of said duplexer, for its exclusive use, is controlled so that power is fed or cut off at the AC input unit of the first side of the electric power supply. For other units mounted as an option additionally, a similar power supply is constituted.
An optional unit such as an exclusive power supply to supply power to each part in the duplexer, is provided in said duplexer, and the electric power is fed or cut off from the unit power supply to each component in the unit using a control signal of the control device in the color electrophotography apparatus. Generally when feed/cut of the electric power is performed in the secondary side of the power supply (5V/24V generation part), even if there is not any supplied power from the secondary side, the electric power is consumed by a loss on the primary side. That is to say, even if, the power supply to an interior part of the unit is stopped by cutting off the secondary circuit, the electric power is consumed in the power supply, and, as a result, a bad influence is exhibited on the power-saving specification value.
In contrast, in accordance with the present invention, the feed/cut off of operation of the unit power supply is performed at the primary side AC input unit of the power supply, so that a condition can be achieved such that any useless power supply does not exist. As the optional unit receives the information of enforcement before the unit power supply is selected to feed/cut off said electric power, for example, when there is a control device having a CPU in the optional unit, the cut/feed of the electric power can be prepared for each component beforehand. On this account, when the function of the unit is unnecessary, for example, in a power-saving mode, when the exclusive power supply in the optional unit is switched off, the power consumption of the system can be reduced, and malfunction of each component in the unit can be prevented.